How do you explain equality in JavaScript?

Question

1. Strict comparison (e.g., ===) checks for value equality without allowing coercion
2. Abstract comparison (e.g. ==) checks for value equality with coercion allowed

var a = "42";

var b = 42;

a == b; // true

a === b; // false

1. 
   

Answer 1

Javascript is a dynamically typed language, meaning that we do not need to specify the variable type because the interpreter does so at runtime. And indeed, in the example, variable "a" is assigned a value type of "string" and variable "b" is assigned a value type of "number".

In this case:

a == b;

Javascript uses coercion, which is simply the process of converting one data type to another. Here, the value 42 gets converted to the string "42".

A strict comparison does not allow for type coercion, and therefore the comparison:

a === b;

is false.